Exocrine glands have many key functions in the body, ranging from production of digestive enzymes to secretion of fluids for protection from desiccation. Exocrine gland defects, such as those that occur in cystic fibrosis are presently poorly understood. The study of the secretory process in exocrine glands has been hampered by their complex morphology, anatomical inaccessibility and heterogeneity of the secretory elements. By studying the glands in the isolated intact frog skin we can measure simultaneously the electrical and ionic events that occur during the resting and catecholamine-stimulated condition and correlate these with morphological alterations in gland structure. Gland function can be isolated from the responses of the skin by the use of the amiloride-inhibited in vitro skin preparation. Furthermore, results can be verified by studying ionic and electrical events in the "split skin" which is free of glands. In addition, we can obtain an isolated acini preparation which will allow us to examine directly the ionic events that occur across the cell membrane of the secretory cells in the resting and stimulated state. Also, we will further develop and utilize our method for measuring water flux across epithelia (scanning micropipette mass spectrometer) to analyze the responses of individual glands. Since the skin glands of the frog have long been studied for their evolutionary relationship to mammalian sweat glands this research should provide new information on exocrine gland structure and function and lead to further understanding of the disease processes that specifically affect these glands.